* {
    box-sizing: border-box;
    margin: 0;
    padding: 20px;
    transition: background 800ms;
  }
  
  html {
    height: 100%;
    background: hsl(193, 66%, 55%);
    font: bold 40px helvetica, sans-serif;
    color: red;
  }
  
  body {
    height: 100%;
    background: hsl(193, 66%, 65%);
  }
  
  div {
    height: 100%;
    background: hsl(193, 66%, 75%);
  }
  
  ul {
    height: 100%;
    list-style: none;
    background: hsl(193, 66%, 85%);
  }
  
  li {
    height: 100%;
    background: hsl(193, 66%, 95%);
  }
  
  .highlight {
    background: red;
  }